Lunar Module Problems and Another Change of Mission

A lunar module arriving at KSC aboard the Super Guppy, June
1967.

The uncertainty about the Apollo 8 mission, temporarily relieved by the
progress on Apollo 6's deficiencies, reappeared in June when KSC began
testing lunar module 3. Although it was to have arrived in flight-ready
condition, KSC soon found out otherwise. The ascent and descent stages
were delivered separately during the early part of June. Several leaks
appeared during early tests of the ascent stage; one of them required a
redesign and valve change. Early in July, a damaged flight connector in
the rendezvous radar of the spacecraft caused a delay in its final
installation. A week after this, there was a meeting at KSC of Houston,
Grumman, and KSC officials to resolve the modification requirements. KSC
estimated that it would take four days to complete the approved
modifications prior to altitude chamber operations. An additional three
to four days might be required if other pending modifications were
approved. While work proceeded around the clock, engineers began a
combined systems test for the spacecraft on 17 July. Problems with the
radar, guidance, and communications systems delayed completion of the
test for three days.54

During July, KSC was also investigating an electromagnetic interference
problem in which the rendezvous radar locked onto the telemetry signal.
Filters sent from the Grumman plant did not correct the problem.
Attempts to tune the coaxial connection between the radar dish and the
electronics package lessened the interference with the telemetry system,
but resulted in a new interference with the abort guidance system. On 2
August when the spacecraft internal systems were activated,
electromagnetic interference increased and further investigation began.
As George M. Low later recalled, it was about this time that a
circumlunar mission without a lunar module first appeared as a real
possibility. Difficulties encountered at KSC were having their impact on
decision-making at headquarters.55

The S-II second stage had gone immediately to the low-bay transfer aisle
after its return on 27 June. Between 1 and 11 July, the augmented spark
igniters in the five engines were changed. When the second stage was
erected on 24 July, the third stage was still undergoing modification.
Forecasts that the instrument unit's flight control computer would not
arrive on time threatened the schedule. Between delays in the delivery
of launch vehicle hardware and difficulties with the lunar module
rendezvous radar, the period of late July and early August was critical.
Without a firm decision from headquarters, KSC could not move
effectively, and difficulties at KSC tended to preclude firm
decisions.56

At a Management Council Review in Houston, 6-7 August, Low presented the
details of the lunar module problems and asked the Houston mission
director, Christopher C. Kraft, to look into the feasibility of a lunar
orbit mission without a lunar module. Low noted that the KSC work
schedule was currently headed for a January 1969 launch and that
insistence upon the use of lunar module 3 could result in a delay of up
to two months. At a second meeting on 9 August, Kraft reported that the
lunar orbit mission was feasible. Debus indicated that KSC could support
such a launch as early as 1 December. Only two items remained open: the
location of a suitable substitute for the lunar module and the approval
of the Administrator, who was overseas at the time. Within three days
after the meeting, the command and service modules for Apollo 8 had
arrived at KSC.

At a meeting in Washington on 14 August, NASA substituted a test article
for the lunar module. Since the circumlunar mission depended on KSC's
ability to support a 6 December launch, Debus was asked to assess the
launch team's chances. The KSC director replied that he had no technical
reservations. Although Mueller expressed a reluctance to decide before
Apollo 7 results were evaluated, he conceded the necessity of doing so.
The overall review of the circumlunar mission plan resulted in an
informal "go." KSC's response was immediate and positive: the
following day, the spacecraft facility verification vehicle was erected
on the instrument unit.

Administrator Webb agreed on 17 August to man Apollo 8 for an
earth-orbital mission, but postponed the decision on a circumlunar
mission until after the Apollo 7 flight. The launch of Apollo 8 was set
for 6 December. On 19 August, General Phillips announced the earth-orbit
mission to the press in Washington. He ascribed the change to the
problems with the lunar module, then six weeks behind schedule.57 To expedite prelaunch operations for
Apollo 8, Phillips relieved KSC of much of the burden for hardware
modification. The appropriate development centers were given the
responsibility with the understanding that only changes necessary for
crew safety would be accomplished.58

In mid-September KSC completed the first ten parts of the launch vehicle
malfunction test satisfactorily; part 11 was scrubbed because of a
failure in the RCA 110A computer. A modification of the computer in the
launch control center delayed the plugs-out test until 18 September. At
this point the spacecraft was approximately 5 days behind the 10
September schedule.59

NASA conducted a delta design certification review on 19 September by
means of a teleconference. Since Boeing had not yet completed the
testing and analytical work associated with pogo, Phillips asked MSFC to
recommend a date in November for the final review of the Saturn V. Two
days after the spacecraft was added to the launch vehicle stack, Apollo
8 rolled out to the pad on 9 October.60 During the remainder of the month,
the launch team conducted a series of space vehicle tests. The flight
crew participated in several, such as verifying the performance of the
command, control, video, and optical systems in support of the abort
advisory system. They were also active in emergency egress training.
Unlike earlier programs in America's manned space effort, the crew did
not spend a great amount of time with the actual flight vehicle.61

The Apollo 7 mission ended with splashdown on 22 October. Six days
later, NASA outlined the steps that would lead to a final decision on
the next manned Apollo during the week of 11 November. Dr. Thomas O.
Paine, acting Administrator, said: "The final decision on whether
to send Apollo 8 around the moon will be made after a thorough
assessment of the total risks involved and the total gains to be
realized in this next step toward a manned lunar landing. We will fly
the most advanced mission for which we are fully prepared that does not
unduly risk the safety of the crew."62 On 12 November NASA made its
decision public - Apollo 8 would fly a lunar-orbital mission beginning
21 December.63